Washington in the Obama era seems bent on imposing “solutions” that not only fail to solve Americans’ problems, but make us poorer in the bargain.

In a direct attack on Wall Street, the president and his ally, Sen. Blanche Lincoln (D-Ark.), are bent on imposing the “Volcker rule,” which would prohibit banks from making speculative investments with their own funds, and on requiring banks to divest their derivatives trading desks, or at least put them in a separate subsidiary owned by a parent holding company. Five major banks — Bank of America, Citigroup, Goldman Sachs, JP Morgan and Morgan Stanley — do 90 percent of US derivatives trading.

This may ultimately make banking less stable, while forcing a good deal of securities trading out of New York to offshore locations.

The recent credit crisis was caused by 1) banks (small and large) writing shoddy mortgages and 2) inadequately backed derivatives, called swaps, that insured the mortgage-backed

securities that financed those loans.

Money was lent to homeowners who simply did not have the ability to repay their debts — and instead relied on a continuous cycle of refinancing, borrowing more and more as housing prices rose.

Those loans were bundled into bonds (one or two thousand in each batch) and sold to fixed-income investors such as foreign governments with dollars to park, insurance companies and pension funds. Those investors insured their principal by buying swaps from AIG and others.

When the housing market stalled and prices stopped rising, homeowners in over their heads couldn’t refinance and defaulted on their mortgages. AIG and others misgauging the risks had inadequate resources to back up the policies they wrote. AIG and two other venerable nonbanking giants with exposure in the subprime-mortgage market (Bear Stearns and Lehman Bros.) failed.

Investments in securities and derivatives trading had little to do with the problems at Bank of America and Citigroup — it was bad loans, not trading, that sunk their balance sheets and required federal bailouts. (BofA also suffered from a Washington-imposed shotgun wedding with ailing Merrill Lynch.)

Hardly any of the 200-plus regional banks that have failed had trading desks — so neither the Volcker rule nor a ban on derivatives trading would’ve saved them.

In fact, nonbanking activities, like securities trading, are helping Bank of America, Citigroup and other Wall Street giants recover from banking losses and rebuild their balance sheets.

Many large companies and investors like doing their borrowing, lending and other investment-banking activities through firms that can complement those activities with sophisticated costumed designed swaps and other derivatives.

Severing derivatives trading from US banks will merely encourage US and foreign businesses to do their banking in London and elsewhere in Europe. Ultimately, New York banks would be forced into weaker business models or to move significant segments of their activities offshore.

US banking would be weaker — and American credit markets more vulnerable.

The story is much the same with the president’s “response” to the oil spill in the Gulf of Mexico: He’s using it to push an energy bill (cap-and-trade) that is designed to raise the cost of fossil fuels — refined petroleum products, coals and natural gas used in manufacturing and gasoline for cars.

Worse, he attempts to justify this with an absurd economic argument: The White House claims that manufacturers aren’t investing in the United States because they don’t know the future price of carbon, and gasoline is so cheap that drivers make wasteful choices.

Nonsense: Manufacturers aren’t investing here because China boosts exports with an artificially undervalued yuan and keeps energy prices cheaper than in the United States by subsidizing refinery purchases of imported crude oil.

The Obama energy bill would only further disadvantage US manufacturers and hasten the exit of American factories to China. (And, since China uses petroleum and other fuels less efficiently, global CO2 emissions would increase, hastening global warming.)

Americans don’t drive more fuel-efficient cars because Detroit, with its plants still hamstrung by union contracts and rigid federal regulations, can’t deploy already available more fuel-efficient designs as quickly as car buyers are willing to scarf them up.

If the president wants to reduce gasoline consumption, he might consider working with automakers to accelerate the transition to more fuel-efficient gasoline-burning platforms while electric-car technology matures and deployment grows over the next two decades.

That, however, would require him to target his policies to addressing the nation’s needs, rather than his own political desires.

Peter Morici is a professor at the University of Maryland’s Smith School of Business and for mer chief economist at the US In ternational Trade Commission.